Tar distillation method and system

The invention relates to the technical field of tar distillation, and discloses a tar distillation method which comprises the steps of S1, pretreating raw material tar; S2, inputting the pretreated raw material tar into a distillation main tower, and distilling until a light component oil fraction is produced; S3, after the output of the light component oil fraction is stable, extracting part of the light component oil fraction from a side line; S4, increasing the temperature of the material at the bottom of the distillation main tower to a certain temperature, and reducing the fuel; S5, pumping out part of the material at the bottom of the main distillation tower, distilling the residual material at the bottom of the main distillation tower, and mixing the residual material at the bottom of the main distillation tower with the raw material tar newly input into the bottom of the main distillation tower; and S6, mixing the material extracted from the bottom of the main distillation tower with the extracted lig